A local power utility claims that the mean annual household electric bill for its subscribers is only $600. A consumer watchdog group wants to dispute this claim. Everyone agrees that the standard deviation σ of annual household electric bills is $150   Some time later, a wealthy activist provides funding for a simple random sample of 250 households. The mean annual electric bill for this sample is $622. Find a 95% confidence interval for the true mean annual electric bill, based on this sample.

A First Course in Probability (10th Edition)
10th Edition
ISBN:9780134753119
Author:Sheldon Ross
Publisher:Sheldon Ross
Chapter1: Combinatorial Analysis
Section: Chapter Questions
Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...
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A local power utility claims that the mean annual household electric bill for its subscribers is only $600. A consumer watchdog group wants to dispute this claim. Everyone agrees that the standard deviation σ of annual household electric bills is $150

 

Some time later, a wealthy activist provides funding for a simple random sample of 250 households. The mean annual electric bill for this sample is $622. Find a 95% confidence interval for the true mean annual electric bill, based on this sample.

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